WASHINGTON — U.S. lawmakers took NASA to task during hearings on the agency’s 2012 budget request March 2-3 for boosting commercial human spaceflight initiatives at the expense of a heavy-lift launch vehicle and space capsule mandated by the NASA Authorization Act of 2010.

Rep. Frank Wolf (R-Va.), chairman of the House Appropriations commerce, justice, science subcommittee that oversees NASA spending, said the bipartisan authorization act that President Barack Obama signed into law last October should have ended a year of contentious debate over the future of NASA’s human spaceflight program.

“Instead the debate has shifted to whether NASA can effectively implement the direction provided by the authorization and places the budget squarely in the middle of the discussion,” Wolf told NASA Administrator Charles Bolden during a subcommittee hearing March 3.

Wolf said the current fiscal climate would force NASA to make tough choices in the coming months in order to execute policy guidance contained in the 2010 law, which recommends $19.45 billion for the space agency next year, roughly $750 million more than the $18.72 billion White House requested.

“Congress has asked a lot of NASA and we need to seriously consider whether we can afford to simultaneously maintain our human exploration program and support the extension of the [international] space station and continue with flying science missions, advance commercial spaceflight and engage in NASA’s many other activities,” Wolf said.

Bolden said NASA is doing its best to work within fiscal constraints as the Obama administration comes under increasing pressure by the GOP-led House of Representatives to curb federal discretionary spending.

“When the president submitted his 2011 budget, the world was different,” Bolden said, referring to the $19 billion spending plan Obama sent lawmakers in February last year.

But despite the bleak fiscal forecast, Wolf and other House lawmakers questioned NASA’s decision to request less funding than  recommended in the authorization bill for the new heavy-lift launch vehicle and space capsule that the law says should be operational by 2016.

“Your request has certainly sacrificed progress on the development of the Space Launch System and Multi-Purpose Crew Vehicle,” Wolf said, referring to the $2.8 billion NASA requested for the efforts next year, $1.2 billion less than the roughly $4 billion authorized in the law. “The levels provided in your budget for these activities virtually guarantee that NASA won’t have core launch and crew capabilities in place by 2016.”

In testimony before the House Science, Space and Technology Committee a day earlier, Bolden said NASA would be hard-pressed to build the rocket and space capsule within the funding and schedule guidelines set forth in the law.

“Given the level of funding in the 2010 authorization act, you have now made it very difficult for me to execute the development of a heavy-lift launch vehicle and a Multi-Purpose Crew Vehicle that is flying in 2016,” Bolden told Rep. Ralph Hall (R-Texas), who chairs the committee. “I have not said I cannot do that but I don’t want to mislead anyone and make them think that we can do it.”

Hall said his committee takes the 2010 NASA Authorization Act seriously and expects the agency to abide by the policy direction and funding ceilings it sets. He also said NASA must “cease its efforts to delay resumption of full development of an assured access system,” a reference to the law’s direction that the new heavy-lift launch vehicle and space capsule serve as a backup to commercially provided crew access to the space station.

However, Bolden said NASA would have no use for a heavy-lift rocket and deep space capsule before the end of this decade.

“There may be available systems before that time, but I don’t need one for beyond low Earth orbit until 2020,” he said.

Instead, Bolden said, his priority is to ensure a domestic, commercial capability is available by mid-decade to deliver astronauts to the space station, which he described as the anchor for all future manned exploration and the sole destination for U.S. astronauts during the next 10 years.

“That’s our Moon right now,” he told Rep. Michael McCaul (R-Texas) during the March 2 hearing. “That’s where we do technology development, that’s where we do medical research, that’s where we do things to make life better on Earth.”

But some lawmakers were skeptical.

Rep. Steven Palazzo (R-Miss.), a freshman who chairs the panel’s space and aeronautics subcommittee, questioned Bolden’s optimism.

“How can you be confident that the commercial crew and cargo [systems] are sufficiently mature enough to justify a firm, fixed- price contract?” he said, referring to new rockets and cargo capsules being developed by Orbital Sciences Corp. and Space Exploration Technologies Corp. under NASA’s Commercial Orbital Transportation Services (COTS) program. Both companies signed firm, fixed-price contracts worth a combined $3.5 billion in December 2008 to begin routine resupply runs to the space station following successful completion of the COTS demonstration program, though both providers have experienced delays in meeting hardware development milestones.

Bolden said he is confident that commercial space firms can deliver.

“At least one has been doing it for more than 20 years,” Bolden said, citing Orbital Sciences, one of several references made during the hearing to the well-established Dulles, Va.-based company.

“I’m not concerned about their ability to deliver,” he said.